Precautions Before Welding S35C Steel Plate

S35C steel plate, a medium carbon steel under the JIS G 4051 standard, is widely used in structural components and machinery parts due to its good strength and machinability. However, welding S35C requires careful preparation to avoid defects such as cracking or distortion caused by its relatively high carbon content.

One of the key precautions before welding S35C steel plate is preheating. Typically, the steel should be preheated to 150–250°C depending on its thickness. This reduces thermal stress and helps minimize the risk of cold cracking during and after welding.

Proper joint design is also critical. When welding thick plates or critical components, using V-groove or double-V grooves can improve penetration and reduce residual stress. The choice of filler material is equally important — low-hydrogen electrodes or compatible welding wires are recommended to prevent hydrogen-induced cracking.

Additionally, post-weld heat treatment (PWHT) is advisable, especially when the welded component will face dynamic loading. PWHT helps relieve internal stress and restores ductility.

Before welding, ensure the surface is clean and free from oil, rust, or moisture to maintain weld integrity. By following these precautions, fabricators can achieve strong, reliable welds on S35C steel plate and enhance the overall performance of the final product.